Scaffold-support.



No. 796,807. PATENTED AUG. 8, l905.

Y M. GAVANAGH.

SCAPFOLD SUPPORT.

APPLIoATIoN HLBD Nov. 22.1904.

2 SHEETS-SHEET 1.

c IJJ Z Aunktw. a. cnam co. Paare-uwsanxanzns msuwcmw. c. c.

PATENTED AUG. 8, 1905.

M. CAVANAGH. SCA-IFOLD SUPPORT.

APPLICATION FILED Nov. 22, 1904.

2 SHEETS-s115217 2.

Gmwms. wnsmuurou. u. c,

uNrTnD sTAgins PATENT OFFICE.

MICHAELl CAVANAGH, OF NEW YORK, N. Y.

SCAFFOLD-SUPPORT.

Specicaton of Letters Patent.

Patented Aug. 8, 1905.

Application filed November 22, 1904` Serial No. 233,811.

. ments in the scaffold-support for which Letters Patent were granted toWilliam J. Murray on September 6, 1904, No. 769,395, said improvementsbeing designed with a view of remedying some of the defects of thescaffoldsupport referred to and to permit the quicker and more effectiveoperation of the same when raising or lowering the scaold; and for thispurpose the invention consists in the novel features and combinations ofparts, which will be fully described hereinafter and finally pointed outin the claim.

In the accompanying drawings, Figure l is a front view of a part of thewall of a building, showing my improved scaffold-support suspended fromthe steel or iron frame of the building. Fig. 2 is a vertical transversesection on line 2 2, Fig. l. Fig. 3 is a side view of oneof my improvedscaffold-supports. Fig. 4 is a plan view of Fig. 3; and Fig. 5 is avertical transverse section of said scaffold-support on line 5 5. Fig.3.

Similar letters of reference indicate corresponding parts.

Referring to the drawings, c designates a portion of a Wall of abuilding, which wall is built around and incloses the usual steel oriron framework composed of horizontallyarranged beams b and verticalcolumns or supports The framework of the building is also provided withhorizontally arranged beams b2, which are placed at right angles to thefront beams b, as shown in Fig. 2. As the Wallis raised and the erectionof the building progresses, it is necessary to supply the material forthe surrounding and partition walls, for which purpose it is customaryto provide al scaffold c, which has to be raised as the wall is raisedand the erection of the building gradually continued. The scaffold c issupported at either end by means of ropes f g, which are attachedattheir lower ends by means of eyes to hooks on the scaffold and whichare wound up on two parallel drums f g', that are supported on ahorizontal frame which comprises two parallel beams CZ, that are placedtransversely to the wall beam or beams b and extend suliiciently forwardfrom the same so as to permit the free raising and lowering of thescaffold c, suspended from the ropes. The inner ends of the beams dl areattached to the supplemental transverse beams Z2 of the framework of thebuilding by means of locking-yokes or other locking devices 0l', so asto be firmly held in position thereon. The beams d are preferablyarranged in pairs, as shown in Figs. 1 and 4, and serve for supportingthe framework e, on whichthe journal-bearings of the parallel drums f gare supported. The frame is made in the form of parallel sideangle-irons e2 and transverse connecting members e3, said angle-ironsresting on the beams Z of the framework and being attached thereto inany suitable manner, so as to prevent their shifting on thesupporting-beams. To the angular side rails of the frame Je are attachedthe journal-bearings for the shafts of the drums f g', which drums areprovided at one end with worm-gears f2 g2, which mesh, respectively,with right and left hand worms f 3 g3 of a worm-shaft s, which issupported in bearings at the upper ends of upright supports e', as shownclearly in Figs. 3 and 4. An actuating device for said wormshaft isoperative from the scaffold to turn the shaft in either direction forraising or lowering the scaffold. The actuating device shown for thispurpose will now be described. To the end of the worm-shaft s isattached a sprocket-wheel t, over which is passed an endlesssprocket-chain L, which is of sufficient length to extend in downwarddirection nearly to the scaffold c. Separate locks are provided for eachdrum to render the scaold safe in case the thread of either worm shouldbecome worn or for any reason be disengaged from its worm-gear. This isimportant, because the disengagement of the worm-gearing for either drumwould precipitate the occupant of the scaffold to earth. For conveniencein operation-and to avoid a multiplicity of parts a releasing devicecommon to both said locks' is operative from the scaffold. By such meansthe operator on the scaffold may release both locks with one hand andraise or lower the scaffold with the other. The opposite ends of thedrums f g are provided with ratchetwheels t', the teeth of which extendin opposite directions and which are engaged by pawls z', that arepivoted to upright supports on the framework e, said pawls beingprovided with downwardly-extending arms 2, which are connected at theirlower ends by ropes or other flexible connections 3 with the connectingringer link c of a rope or similar connection i, that extends indownward direction to the scaffold, so as to be conveniently taken holdof by the man on the scaffold whenever it is desired to release thepawls or drop the same for locking the drums.

By operating the sprocket-wheel chain the worm-shaft is turned and thedrums rotated in opposite direction to each other by the worm-geartransmission. The suspensionropes f and g on which the scaffold issuspended are wound upon the drums in opposite directions, one rope, f,being attached to one end of the drum, while the rope g is attached tothe opposite end of the drum, so that the strain exerted by thesuspensionropes on the drums, being in opposite direction, balance eachother and produce thereby the even winding of the ropes on the drums,the ropes extending in downward direction at the outer circumference ofthe drums, Iso as to provide the distance required by them forsuspending the scaffold without the necessity of any guide-pulleys forone or both suspension-ropes.

The scaffold can be raised and instantly stopped at any desired pointowing to the wellknown locking action on the motion-transmittingworm-gears. While the scaffold is raised by the worm-gear mechanismdescribed the drums are turned toward each othe r, while the pawls passover the teeth of the ratchetwheel and are always held in lockingengagement with the same, so that no danger of any slipping of thesuspension-ropes under the weight placed on the scaffold is possible,the ratchet-wheel and pawl mechanism serving as an auxiliarysafety-guard for the locking action of the worm-gear transmission. Whenthe scaffold. is to be lowered, the pawls have to be released from theteeth, so as to permit the downward motion. For this purpose the ropet'5is pulled, which lifts the pawls and withdraws them from the teeth ofthe ratchetwheels. The pawls are held out of engagement with theratchet-Wheels by the rope until the lowering motion is completed, whenthey are permitted to drop again into engagement with the teeth of theratchet-wheels. The scaffold-support is moved to the points required onthe steel or iron framework of the building to be erected and also forthe higher stories of the building as the erection of the sameprogresses.

The advantages of my improved scaffold-support are, first. that theconstruction is considerably sim pliiied; second', that the speed atwhich the scaffold can be raised or lowered is considerably increased;third, that the perfect safety and reliability of the scaffold isobtained owing to the combined action of the worm-gear andpawl-and-ratchet mechanism; fourth, that the suspension-ropes beingarranged at the outside of the drums and wound up in diagonally oppositedirections on the same prevent any uneven strain on the drums andproduce the even winding on and unwinding of the suspension-ropes fromthe drums.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- A scaold -support comprising a frame, winding-drumssupported thereby parallel to each other, suspension-ropes wound andunwound from said drums and adapted for connection with opposite ends ofthe scaffold,

worm-gears in fixed relation to said drums, a worm-shaft supported onsaid frame and provided with worms engaging said worm-gearsrespectively,means operative from the scaffold to turn said shaft ineither direction for raising or lowering said scaffold, separateauxiliary safety-locks for the respective drums, and a releasing devicecommon to said locks and operative from the scaffold.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

MICHAEL CAVANAGH.

Vitnesses:

PAUL GonPnL, HENRY J. SUHRBIER.

